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Will Deacon 1403a89915 arm64: sme: Use STR P to clear FFR context field in streaming SVE mode 
[ Upstream commit 893b24181b ]

The FFR is a predicate register which can vary between 16 and 256 bits
in size depending upon the configured vector length. When saving the
SVE state in streaming SVE mode, the FFR register is inaccessible and
so commit 9f58486657 ("arm64/sve: Make access to FFR optional") simply
clears the FFR field of the in-memory context structure. Unfortunately,
it achieves this using an unconditional 8-byte store and so if the SME
vector length is anything other than 64 bytes in size we will either
fail to clear the entire field or, worse, we will corrupt memory
immediately following the structure. This has led to intermittent kfence
splats in CI [1] and can trigger kmalloc Redzone corruption messages
when running the 'fp-stress' kselftest:

 | =============================================================================
 | BUG kmalloc-1k (Not tainted): kmalloc Redzone overwritten
 | -----------------------------------------------------------------------------
 |
 | 0xffff000809bf1e22-0xffff000809bf1e27 @offset=7714. First byte 0x0 instead of 0xcc
 | Allocated in do_sme_acc+0x9c/0x220 age=2613 cpu=1 pid=531
 |  __kmalloc+0x8c/0xcc
 |  do_sme_acc+0x9c/0x220
 |  ...

Replace the 8-byte store with a store of a predicate register which has
been zero-initialised with PFALSE, ensuring that the entire field is
cleared in memory.

[1] https://lore.kernel.org/r/CA+G9fYtU7HsV0R0dp4XEH5xXHSJFw8KyDf5VQrLLfMxWfxQkag@mail.gmail.com

Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: 9f58486657 ("arm64/sve: Make access to FFR optional")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Link: https://lore.kernel.org/r/20230628155605.22296-1-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-07-19 16:36:25 +02:00
arch arm64: sme: Use STR P to clear FFR context field in streaming SVE mode 2023-07-19 16:36:25 +02:00
block block: increment diskseq on all media change events 2023-07-19 16:36:22 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation dt-bindings: qcom-qce: Fix compatible combinations for SM8150 and IPQ4019 SoCs 2023-07-19 16:36:19 +02:00
drivers efi/libstub: Disable PCI DMA before grabbing the EFI memory map 2023-07-19 16:36:24 +02:00
fs ksmbd: avoid field overflow warning 2023-07-19 16:36:24 +02:00
include block: change all __u32 annotations to __be32 in affs_hardblocks.h 2023-07-19 16:36:22 +02:00
init kbuild: Fix CFI failures with GCOV 2023-07-19 16:36:23 +02:00
io_uring io_uring/net: use the correct msghdr union member in io_sendmsg_copy_hdr 2023-06-21 07:34:17 -06:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel kcsan: Don't expect 64 bits atomic builtins from 32 bits architectures 2023-07-19 16:36:13 +02:00
lib lib/ts_bm: reset initial match offset for every block of text 2023-07-19 16:35:37 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm splice: Fix filemap_splice_read() to use the correct inode 2023-07-19 16:35:07 +02:00
net SUNRPC: Fix UAF in svc_tcp_listen_data_ready() 2023-07-19 16:36:22 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples/bpf: xdp1 and xdp2 reduce XDPBUFSIZE to 60 2023-07-19 16:35:25 +02:00
scripts kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb 2023-07-19 16:36:24 +02:00
security apparmor: fix: kzalloc perms tables for shared dfas 2023-07-19 16:36:21 +02:00
sound ALSA: pcm: Fix potential data race at PCM memory allocation helpers 2023-07-19 16:36:21 +02:00
tools tools/testing/cxl: Fix command effects for inject/clear poison 2023-07-19 16:36:23 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.3 2023-07-11 06:31:05 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.